Tool for compressing a biasing spring of an electric drum controller



Aug. 9, 1960 M. CULKOSKY TOOL FOR COMPRESSING A BIASING SPRING OF AN ELECTRIC DRUM CONTROLLER Filed Aug. 30, 195'? INVENTOR MART/N CULKOS/(Y l -ruw- U Alla/nay United States Patent-'0 TOOL FOR COMPRESSING A BIASING SPRING OF The present invention relates generally to electric drum controllers and more particularly to a spring-compressing tool especially suitable for moving a spring biased collar of 'an electric drum controller against theforce of the biasing spring to facilitate removal and replacement of a contact finger.

Conventional electric :drum controllers ordinarily include a cylinder or drum made up of a plurality of curved copper segments of varying length aflixed along the length of a rotatable shaft which is revolvable by means of a controller handle; an insulated bar adjacent and parallel with the cylinder or drum; a plurality of brackets spaced along the bar; and a pivotal contact finger on each bracket. The contact fingers extend toward the cylinder and are adapted to tangentially contact one of the copper segments thereof. Each of the contact fingers is pivotally mounted on its support bracket by means of a spring loaded shaft or bolt so that the contact finger is constantly urged toward the cylinder. A helical compression spring is disposed on the mounting shaft with one end bearing against the finger and its other end bearing against a collar held on the shank of the bolt by means of the keeper pin.

Due to the friction contact of the contact tips of the fingers with the curved copper segments and the sparking between the contact tips and the segments, the tips wear within a short time and necessitate frequent replacement of the contact fingers.

In replacing any of the contact fingers it is necessary to remove the finger biasing spring from the mounting bolt before the finger can be removed. Before the spring can be removed the keeper pin, usually in the form of a cotter pin, must be removed from the end of the bolt. In removing the keeper pin, the spring is first compressed and the collar is moved along the bolt away from the pin.

Prior to my invention, for the purpose of assembly or disassembly of the contact finger, the bias spring was compressed manually by grasping the collar at the bottom of the spring with the thumb and forefinger of one hand or with a pliers. At best, such manual operation was excessively time consuming and frequently resulted inpinched and scratched fingers.

It is accordingly, the primary object of the present invention to provide a simple tool for quickly and easily compressing a finger-biasing spring of an electric drum controller to facilitate replacement of a contact finger.

This and other objects will become more apparent after referring to the following specification and attached drawings, in which:

Figure 1 is a side elevational view of the tool of the invention showing it being applied to an electric drum controller;

Figure 2 is a view similar to Figure 1 showing the tool in operative position;

Figure 3 is a view in perspective of the tool of the invention; and

Figure 4 is an end view of Figure 3.

Referring more particularly to the drawings reference Ice 2 numeral 2; designates generally the tool of my invention whichisused as shown in Figures 1 randZ, to comprms a finger-biasingspring 40f an electric drum controller 6,.

and move a collar 8 of the controller away fromits keeper pin 10 to facilitate removal of the pin.

Asbest-seen in Figure 1,, controller 6 includes a cylinder'12- mounted on an insulated rotatable shaft 14. An

insulated bar- 16 is disposed adjacent to and parallel with the-cylinder-1 2jand has a plurality of contact finger brackets 18--(oneof which is shown) mounted in spaced relation "therealong. A contact finger 20 is pivotally mounted on each of thebrackets 18 by means of a bolt or shaft 22 which passes through the bracket and the contact-finger: The contact finger is constantly urged toward the cylinder '12 by means of the helical compression spring 4 which is circumferentially disposed on the shank of the bolt 22 and bears at one end against the contact finger and at its other end against the collar 8 afiixedto the end of the portion of the bolt shank project-- ing from the contact finger. The keeper pin 10, which may be in the form of a cotter pin, is removably inserted in the end of the shank of the bolt to keep the collar on the bolt.

The structure of the electric drum controller as just described is conventional and is not claimed as part of the present invention but has been described to insure a clear understanding of the structure and mode of functioning of the tool of the present invention.

The tool 2 is formed with a handle 30 having a prong 32 extending from one end thereof. Prong 32 includes a pair of spaced legs 34 extending from and co-planar with one end of the handle 30. The legs 34 are parallel with each other along the majority of their lengths. The ends 36 of legs 34 remote from the handle 30 diverge from each other and project at an angle from the plane containing the handle, as best seen in Figures 3 and 4, and form an entry guide for the space between the legs 34. The space between the parallel portions of legs 34 is greater than the diameter of the shank of bolt 22 and cotter pin 10 but less than the diameter of the collar 8.

A pair of spaced parallel legs 38 is integral with pair of legs 34 and extends from legs ends 36 in a plane substantially normal to the plane containing the handle 30.

A pair of spaced parallel legs 40 is integral with pair of legs 38 and extends normal to legs 38 in the direction toward the handle 30.

The space between the legs 38 and betwen legs 40 is sufficient to receive finger bracket 18 and contact finger 20. I have shown the tool of the invention preferably formed from a single length of square or rectangular section rod, the prong 32 being a continuation of the handle 30 and the legs 34 fixed in spaced relationship by means of a clamp 42 secured to the legs by means of a screw 44. If desired the handle and prong may be made separable and the handle may be made of material diftferent from that of the prong. The prong is preferably made of hard steel.

In operation, when it is desired to compress spring 4 so that the collar 8 can be moved away from the cotter pin 10, the tool of the invention is first applied to the controller as shown in Figure 1 with the angulated ends 36 of legs 34 resting on the collar 8 and legs 40 resting on bar 16 astride the bracket 18 and contact finger 20. A downward force is then applied to the handle 30 as in-' dicated by the arrow in Figure 1. This causes the legs 40 to pivot on bar 16 and the legs 34 to compress the spring 4 and move the collar 8 away from the cotter pin 10 for easy removal or insertion thereof.

While one embodiment of my invention has been shown and described, it will be apparent that other adaptations and modifications may be made without departing from the scope of the following claim.

I claim:

A tool for moving a biased collar along a shaft against the force biasing the collar of an electric controller having a bar, a bracket rigidly disposed on the bar, 'a contact finger carried by said bracket, said shaft projecting from said bracket and through said contact finger and mounting said finger on said bracket, said collar being slidably mounted on said shaft, a collar keeper pin removably disposed on said shaft on the end thereof remote from said bracket and finger, said biasing force being a helical compression spring circumferentially disposed on' said shaft with one end normally bearing against said finger and the other end normally bearing against said collar, which tool comprises a handle, a first pair of spaced legs extending from said handle, said legs being parallel along the majority of their lengths, the ends of said legs remote from said handle diverging laterally from each other, said legs being adapted to receive said shaft and keeper pin therebetween but not said collar, a second pair of spaced parallel legs integral with said first pair of legs and ex-- tending from said ends of said first pair of legs substantially normal thereto, and a third pair of spaced parallel legs integral with and extending normal to said second pair in the direction of said handle and parallel to the longitudinal axis of said first pair of legs, the legs in each of said second pair and of said third pair being spaced apart a substantially uniform distance, said distance being greater than-the distance between the legs in said first pair, the legs of each of said second pair and of said third pair being adapted to engage said contact finger and said bracket therebetween, the space between said first pair of legs and said, third pair of legs .being of such dimension that said spring is compressed and said collar is moved axially of said shaft away from said keeper pin when the tool is applied to said drum controller with said first pair of legs astride said shaft between said collar and said keeper pin and said third pair of legs bearing on said bar astride said bracket and said contact finger.

References Cited in the file of this patent UNITED STATES PATENTS' 

